Length-weight relationship, body condition, and fishing gear selectivity of shortfin scad (Decapterus macrosoma) landed in Banjarmasin fishing port, Indonesia
The present study provides scientific information on the growth pattern and relative condition of shortfin scad, Decapterus macrosoma Bleeker landed in Banjarmasin fishing port, Indonesia. A total of 313 individual scad comprising 178 males and 135 females ranging from 152 to 225 mm total length and from 37 to 110 g weight were investigated. The body shape of both males and females showed isometric growth patterns indicating that all body dimensions grew at the same rate. The regression coefficient was significantly different between the sexes. The total length (TL), body weight (W), body depth (BD), W/TL, and BD/TL ratios and condition factors of the females were comparatively higher than those of males. The highest percentage of the catch was between 180 and 189 mm TL (32.59–40.45%) and 50 and 59 g W (20.65-21.79%). The relative condition factor values ranged from 0.799 to 1.433, which reflected the good condition of the fish samples. The estimated length at first capture (Lc50) and selection factor values were 180 mm and 3.54 for males and 185 mm and 3.64 for females. In the present work, the purse seine was considered to be a male-biased gear, with a sex ratio of 1.3 : 1. The outcomes of this research could be useful for sustainable pelagic fisheries management and for developing precautionary measures to prevent the overexploitation of this species.